Obstructive sleep apnea (OSA) may cause early cognitive decline in otherwise healthy patients. The corresponding study was published in Frontiers of Sleep.
OSA happens when the throat muscles relax and block airflow to the lungs while sleeping. People with the condition stop breathing multiple times per hour, causing symptoms including restless sleep, loud snoring, daytime sleepiness, and prolonged headaches in the morning.
Studies show that 15-30% of men and 10- 15% of women have the condition- or 1 billion adults worldwide. However, it is estimated that 80% of people with OSA are unaware that they have it.
In the current study, researchers studied a group of 27 men aged between 35 and 70 years old who had received a new diagnosis of mild to severe OSA without co-morbidities. They also included seven men as controls without OSA who were matched for age, BMI, and education. All participants underwent tests for cognitive function.
In the end, they found that participants with severe OSA had poorer vigilance, executive function, short-term recognition memory, and social and emotion recognition than controls. While participants with mild OSA performed better than those with severe OSA, they performed worse than matched controls.
The authors noted that intermittent low oxygen and high carbon dioxide in the blood, alongside changes in blood flow to the brain, sleep fragmentation, and neuroinflammation, may explain the cognitive deficits in those with OSA compared to controls.
“This complex interplay is still poorly understood, but it’s likely that these lead to widespread neuroanatomical and structural changes in the brain and associated functional cognitive and emotional deficits,” said Dr. Ivana Rosenzweig, a neuropsychiatrist who heads the Sleep and Brain Plasticity Centre at King’s College London, lead author of the study, in a press release.
“Our study is a proof of concept. However, our findings suggest that co-morbidities likely worsen and perpetuate any cognitive deficits caused directly by OSA itself."
“What remains to be clarified in future studies is whether co-morbidities have an additive or synergistic effect on the latter deficits, and whether there is a difference in brain circuitry in OSA patients with or without co-morbidities," she concluded.
Sources: EurekAlert, Frontiers of Sleep